This invention relates to an anaerobic adhesive composition which possesses excellent adhesive force.
An anaerobic adhesive composition is generally kept in liquid state as long as it remains in contact with air or oxygen, while it is rapidly cured by polymerization under the exclusion of the air or oxygen. Thus, it is widely utilized as sealing materials, such as for loosening prevention materials for threaded-together bolts and nuts, adhesives for mating portions of a bearing or a pulley and leak preventing materials for liquid or gas having a high pressure or high temperature.
This composition is utilized, for example, as stated below, when it is used as loosening prevention materials for bolts and nuts. First of all, the screw parts of bolts and nuts are coated with the composition (under this condition, the composition is kept in liquid state since it remains in contact with air), and next, they are mutually tightened.
As a result, air is excluded from the composition and the composition between the surfaces is rapidly cured by polymerization. Accordingly, the composition prevents the bolts and nuts from loosening and furthermore seals the gap between them. It is also utilized as a sealing material for mating portions in the same manner as mentioned above.
Various kinds of anaerobic polymerizable compositions are well known.
Some of them are indicated as follows.
1. Adhesives comprising, as main ingredients, a mixture of 2 -hydroxyethyl methacrylate and organic peroxides.
2. Adhesives comprising, as main ingredients, a mixture of anaerobically polymerizable monomer having the following general formula and organic peroxides. ##STR1## In which, R represents hydrogen, low alkyl radicals having from 1 to 4 carbon atoms, hydroxyl alkyl radicals having 1 to 4 carbon atoms or ##STR2## R' represents hydrogen, halogens, or low alkyl radical having 1 to 4 carbon atoms, R" represents hydrogen, OH or ##STR3## m represents an integer at least equal to 1, for example, form 1 to 8, or from 1 to 4, n represents an integer more than 1, for example, from 1 to 20 or more, and P represents 0 or 1.
3. Adhesives comprising a mixture of a compound having the following general formula and organic peroxides. ##STR4## In which, R represents hydrogen, methyl radical or ethyl radical, n represents an integer from 1 to 8.
The adhesive strength of these materials is relatively small, especially in fitting compression-shearing adhesive force and tensile-shearing adhesive force.